Pressure fluid supply apparatus



United States. Patent [72] Inventor Karl Hiestaud Piullendorf, Musserer,Germany [21] Appl. No. 753,265 [22] Filed Aug. 16, 1968 [45] PatentedDec. 8,1970 [73] Assignee Firma SMW Spanneinrichtungen Schneider, Manzund Weisshaupt OHG Friedrichshafen, Germany a partnership of Germany[32] Priority Sept. 9, 1967 [33] Germany [31 No. 1163,836

[54) PRESSURE FLUID SUPPLY APPARATUS 9 Claims, 1 Drawing Fig.

[52] US. Cl. 92/106, 91/420, 138/44, 277/68, 277/75, 285/131, 285/ 1 90[51] Int. Cl ..F0lb 31/00, F161 15/00 [50] Field of Search 92/ 1 06,119, 163; 277/(lnquire), 68, 69, 70, 71, 72, 75, 206.1; 285/(lnquire),131, 190; 308/(lnquire), 36.2, 135; 138/44 [56] References Cited UNITEDSTATES PATENTS 1.851.723 3/1932 Neidow 92/106X Primary Examiner MartinP. Schwadron AttorneyErnest F. Marmorek ABSTRACT: Admitting means for apressure fluid to a pressure fluid actuated apparatus, the apparatushaving a cylinder element containing pressure fluid actuated means andhaving a cylindrical outer surface. The admitting means comprise a ringthat surrounds said cylinder element and is slightly spaced from theouter surface. The ring has one (or more) annular groove that faces theouter surface of the cylinder element, with pressure fluid conduitsconnected thereto. The cylinderelement has pressure fluid channelsterminating in said cylindrical surface opposite said groove. Forsealing said groove against said cylindrical surface, an annular seal isplaced in said groove.

PRESSURE FLUID SUPPLY APPARATUS The invention relates to means foradmitting pressure fluid to a cylinder element provided, for example,with a piston actuated by the pressure fluid and forming part of ahydraulically or pneumatically operated chuck, clutch or the like. Thepressure fluid admitting means comprise a ring that surrounds saidcylinder element and is connected to pressure fluid supply conduits. Oneor more sealing elements are placed in said ring and/or said cylinderelement. Theinvention is particularly operated chuck, of a clutch o rthe like usually involves difflculties because the sealing means, due tofriction, are often damaged so that there is no perfect pressure fluidsupply.

In order to prevent grinding of the gasket on a rotating cylinder for acompressed air actuated chuck it has been proposed to arrange an axiallymovable groove ring sleeve between a stationary ring connected to thecompressed air supply and the front end of the cylinder which sleeve ispressed against the front surface of the cylinder by the incomingcompressed air. Wear of the sealing sleeve is reduced in this manner;the expense of guiding and holding the ring connected to the compressedair conduit and receiving the seal, however, is considerable.Furthermore, particularly in the case of a cylinder provided with adouble acting piston, itis usually not possible to arrange the pressurefluid supply pipes and the ring associated therewith at the frontsurface of the cylinder because theseelements are adjacent to the otherstructural parts and are therefore not accessible. Placement ofthepressurefluid conduits in the cylinder walls is connected withconsiderable difficulties.

It is accordingly among the principal objects of the present inventionto provide an arrangement for supplying a pressure fluid to a cylinderwhereby the controlled admission of pressure fluid to the pressurechambers of the cylinder is effected in a simple and reliable manner,and wear of sealing elements is substantially eliminated.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The aforesaid objects are obtained, according to the invention, byarranging a ring connected to pressure fluidsupply conduits at theouter, cylindrical surface of the cylinder and guiding said ring at aslight clearance between the ring and the cylindrical surface, and byassociating with each pressure fluid conduit a seal in an annular groovein the cylinder and/or the ring. Each seal in capable of passingpressure fluid therethrough and is provided with sealing lips which areelastically deformable.

For providing each seal with two lips resting on the cylinder and withtwo lips resting on the ring, it s is advantageous to make thecross-sectional configuration of the seal in the form of a double prismor composed of two mirror-symmetrically arranged portions whichincreaseinradial direction with increasing distance from a narrow centerportion. One or more apertures for passing pressure fluid are preferablyprovided in the central portion of the cross section of each seal.

The aforesaid apertures can be arranged to act as throttles.

The lateral surfaces of each seal may have recesses between two lips. Inthis way the effect of the seal is additionally improved.

For holding and guiding the ring, which is connected tothe pressurefluids conduits, one or more grooves or the like may be provided in theouter surface of the cylinder and/or in the ring, wherein the ring isguided in axial and radial directions by means of spacers set in thering and/or the cylinder and layer of synthetic material; and/or theannular groove in the ring and/or the cylinder is provided with a wearresistant layer for example made of molybdenum.

Where the pressure fluid operated means is a piston placed inside acylinder element and has two end faces, and each end face is actuated bya pressure fluid, it is of advantage to place a valve into a suitablerecess in the cylinder-element for controlling the pressure fluidadmission through pressure fluid supply conduits for admitting pressurefluid to one end of the piston and for releasing pressure fluid from thesecond end of the piston. The valve may comprise a double acting piston,for example a piston to both ends of which pressure fluid can beadmitted.

The piston may have a longitudinal section in the form of the letter Hthe web of which forms the center portion of the piston wherein twospaced conduits are provided parallel to the web. These conduitsterminate in the outside surface of the piston individually opposite oneof the channels through which the flow of pressure fluid must becontrolled. A control piston is placed in each of two axial recessesextending from the aforesaid center portion in opposite directions. Eachcontrol piston is adapted to be actuated on by pressure fluid and haspressure fluid channels so arranged as to open or close the aforesaidspaced conduits. Sealing means are provided for sealing said spacedconduits against one another.

An apparatus according to the invention for admitting a pressure to acylinder or similar structural element is characterized by a simplestructure and, above all, by always reliable operating behavior. As thering orannular element connected to the pressure fluid conduits isarranged on the cylindrical outer surface of the cylinder element, andas the seal associated with each pressure fluid conduit is provided withsealing lips and is elastically deformable in its outer diameter, it. isassured that the seal when no pressure fluid acts thereon s will resumeits original configuration whereby it is lifted from the cylinderelement. Therefore, no friction is possible between the seal and thecylinder element, which rotates when the apparatus is in operation, sothat wear and operating disturbances connected therewith are almostcompletely avoided. u

The seal whosesealing lips, due to the double prismatic cross section ofthe seal, come to lie pairwise on the cylinder element and on theannular element when pressure fluid is admitted, very reliably seals theclearance provided between said elements for reducing friction.Arrangement of the apertures or passages in the seal to act as athrottle, and the recesses in the end surfaces of the seal between thesealing lips, considerably assist the sealing effect.

By arranging the ring connected to the pressure fluid conduits on thecylindrical outer surface of the cylinder element avoids the need foradditional building space particularly on the end surfaces of thecylinder element. This arrangement of the ring makes it possible, inalmost all cases, to supply pressure fluid to a cylinder element in asimple manner without any necessity for special holding means and thelike. The operating performance is further improved if the ring issupported by spacers formed according to the invention, for example if awear resistant layer is provided either on the spacers or on theannular. groove that receives the spacers.

The invention and additional objects and advantages thereof will best beunderstood from the following description of an embodiment thereof whenread. in connection with the accompanying drawing, the single view ofwhich is a schematic longitudinal sectional view of a pressure fluidactuated apparatus equipped with fluid admissionmeans according to theinvention.

Means l are provided for supplying a pressure fluid from a supplyconduit 14 to pressure chambers 4 and 5 of a cylinder 2 which forms apart of a power-actuated chuck. An axially movable piston 3 is placed inthe cylinder 2 for actuating the jaws 7 of the chuck. The piston 3 isconnected to the jaws 7 through an intermediate .element 6 and helicalgears, not shown, so that the jaws 7 are radially moved when the piston3 is moved.

The pressure fluid supply means 1 comprises a distributing ring 13 thatis mounted on the exterior surface 8 of the cylinder 2 and is slightlyspaced therefrom; the ring 13 is held by spacers 24, 25 that areinserted in an annular groove 23 provided in the exterior surface 8 ofthe cylinder 2. In order to reduce the friction between the cylinder 2and the spacers 24, 25 the latter may be in the form of threaded bolts24 provided with a protuberance 25 made of wear-resistant syntheticmaterial. For the same purpose a wear-resistant coat 26, for example alayer of molybdenum, may be sprayed onto the protuberance 25 or into theannular groove 23.

Seals 18 and 19 are inserted in recesses 27, 28, respectively,

in the ring 13 and are associated with pressure fluid conduits 15, 16,respectively. The seals 18 and 19 have a double prismaticcross-sectional configuration, the radial extension of the cross sectionof the seals increasing with increasing axial distance from the centerof the seals. One or more apertures 21 are provided in the seals 18 and19 for throttling the flow of pressure fluid therethrough. Recesses 22are formed in the surfaces of the seals 18 and 19 so that four sealinglips 20 are formed which rest pairwise on the exterior surface 8 of thecylinder 2 and on the ring 13 when pressure fluid is supplied throughthe pressure fluid conduit 15 or 16, depending on the position of theschematically shown control valve 17.

It is of course possible to use seals 18, 19 of a cross-sectionalconfiguration which is differentfrom that shown in the drawing. Forexample, the seals 18 and 19 may have two symmetrically arrangedcross-sectional portions on which, by means of suitable recesses,sealing lips are provided on two or on all four exterior surfaces of theseals. It is of advantage to make the inner sealing lips which areadjacent the cylinder 2, quite strong in order to provide spare wearmaterial in the event the ring 13 comes to rest on the cylinder 2 duringoperation.

For controlling the supply of pressure fluid, a valve 31 is providedwhich is inserted in a recess 32 of the cylinder 2, the recess beingclosed by a plug 37. The valve 31 comprises a piston 33 that has an Hshaped longitudinal sectional configuration. The end surfaces 42 and 43of the piston 33 are exposed to the pressure fluid admitted throughpressure fluid conduits 9 and 11, respectively. A control piston 35 and36, respectively, is placed in the piston 33 on either side of its webportion 34, the control pistons being provided with pressure fluidchannels 40, 41, respectively, and can be moved by the pressure fluidacting on the end surfaces 44 or 45, or 46 or 47, respectively, so thatthe conduits 10 and 12 leading to the pressure chambers 4 and 5,respectively, can be connected to the conduits 9 and 11, by opening orclosing the channels 38 and 39 that are provided in the piston 33 andsealed from one another by a seal 48. 1

When in the illustrated chuck a pressure fluid is to be admitted eitherto the pressure chamber 4 or to the pressure chamber 5, for example, forclamping a workpiece, now shown, by means of the jaws 7, pressure fluidis conducted from the pressure fluid conduit 14 through the controlvalve 17 either into the pressure fluid conduit 15 or into the pressurefluid conduit 16. When the pressure fluid flows into one of the recesses27 or 28 of the distributing ring 13, the seal 18 or 19, respectively,is pressed with the four sealing lips 20 against the cylinder 2 and thering 13, as the apertures 21 act as throttles, so that the clearancebetween the elements 2 and 13 is tightly sealed. The pressure fluid canthen flow through the conduits 9 or 11 provided inthe cylinder 2 to thevalve 31 in order to act on one of the end surfaces, 42 or 43,respectively, of the valve piston 32.

If, for example, pressure fluids flows to the piston 32 through thepressure conduit 11, the piston 32 and the control piston 36 placedtherein will be moved to the left, so that the pressure fluid can flowthrough the channels 41 of the control piston 36 and the channel 39 ofthe piston 32 into the conduit 12 in order to reach the pressure chamberfor acting on the piston 3. The control piston 35 will retain theposition shown in the drawing whereas the piston 32 will be displaced bythe aforesaid action, the pressure chamber 4 will be connected to thechannel 9 through the channel 10, the channel 38 of the piston 32 andthe channels 40 of the control piston 35. The pressure fluid in thepressure chamber 4 can therefore flow without hinderance from thechamber 4 so that the piston 3 is moved to the left by the pressurebuilding up in the chamber 5 and the jaws 7 are displaced accordingly.

lf oil is used as pressure fluid, it may be advisable to connect aseparate return conduit to the control valve 17 for conducting thepressure fluid to an oil sump.

Upon release of pressure fluid, the pressure in the pressure chamber 5will cause the control piston 36 to move to the right (in respect of thesingle view of the drawing) relative to the piston 32 and block the flowof fluid out of the chamber 5. Thus, the piston or actuating member 3will be locked or maintained in its then actuated position. The controlmeans includes the control valve 17, the movable valve or piston valve31 having the piston 33 with recesses 33A and 338 on either side of themiddle of the H section thereof, and control pistons 35 and 36.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

lclaim:

1. A pressure fluid actuated apparatus comprising, in combination:

a cylinder element having a cylindrical outer surface;

pressure fluid operated means disposed in said cylinder element;

channels defined in said cylinder element extending to the exterior ofsaid cylinder element for conducting pressure fluid into and from saidpressure fluid operated means; and

pressure fluid conducting means connected to said cylinder elementoperable for conducting pressure fluid to and from said channels andcomprising:

an annular element placed concentrically about said cylindrical outersurface;

annular clearances being provided between said cylindrical surface andsaid annular element;

annular recesses defined in said annular element and facing saidcylindrical surface, said channels individually originating surfaceopposite said recesses; and

an annular seal placed in each of said recesses actuatable by saidpressure fluid each of said seals having apertures for passing pressurefluid therethrough, and each of said seals having end surfaces providedwith sealing lips for sealing said annular element against saidcylindrical surface.

2. A pressure fluid actuated apparatus, as claimed in claim 1, whereineach of said seals has a cross-sectional configuration including anarrow central portion and two mirror-symmetric portions extending fromsaid central portion substantially parallel to the axis of the seals andincreasing radially with increasing distance from said central portion,said apertures being in said central portion.

3. A pressure fluid actuated apparatus, as claimed in claim 1, whereinsaid apertures form throttles for throttling the pressure fluid passingtherethrough.

4. A pressure fluid actuated apparatus, as claimed in claim 1, whereinsaid sealing lips are annular, one sealing lip extending insubstantially axial direction from the outer periphery of each of saidend surfaces, and a second sealing lip extending in substantially axialdirection from the inner periphery of each of said end surfaces.

5. A pressure fluid actuated apparatus, as claimed in claim 1,comprising an annular groove defined in said cylinder element at andconcentric with the cylindrical outer surface thereof, and spacer meansconnected to said annular element and having a portion extending intosaid groove for axially and radially guiding said annular element.

6. A pressure fluid actuated apparatus according to claim 5 wherein saidspacer means have a portion in threaded engagement with said annularelement, said portion of said spacer means extending into said grooveincluding a wear-resistant coat.

7. A pressure fluid actuated apparatus according to claim 6 wherein saidcoat is made of synthetic material.

8. A pressure fluid actuated apparatus, as claimed in claim 1,comprising an annular groove defined in saidcylinder elehaving a portionextending into said groove for axially and radially guiding said annularelement, and a wear-resistant layer disposed in said groove.

9. A pressure fluid actuated apparatus according to claim 8 ment at andconcentric with the cylindrical outer surface 5 saidlayer being composedb thereof, spacer means connected to said annular element and

